The invention is directed to a chopper arrangement on a combine comprising a web wheel disk having knives entrained thereon.
Straw choppers are used on combines to chop harvested crop material that has been threshed and separated. The straw chopper receives the crop material from the separating assembly and chops the crop material into smaller parts before depositing the chopped crop material onto the field. Known straw choppers are typically equipped with knives supported in bearings pendulously on a rotating body that cut the harvested crop remains in interaction with stationary shear bars. The power requirements are relatively high and the degree of size reduction of the remains is not always adequate.
An undated advertisement for a xe2x80x9cDon Grain Combinexe2x80x9d discloses a drum chopper that can be attached as a straw chopper to the rear side of a combine. The same drum chopper can also be attached to a corn header, in order to chop the harvested crop remains and conduct them into a container or to deposit them on the field.
DE-196 01 421-A describes a corn header in which the ears of corn are conducted to a combine. The plant stems are processed by means of a web disk wheel chopper.
It is an object of the present invention to provide a chopper arrangement for a combine having a low power requirement and a high degree of size reduction of the chopped material.
The large components of harvested crop material that has been threshed and separated by the combine are directed to a chopper arrangement located downstream from the separating assembly. The chopper arrangement is provided with a web disk wheel having radially extending knives entrained thereon. The desired length of the chopped crop material can be controlled by controlling the supply velocity of the crop material to be chopped. This results in a large ejection trajectory and relatively low power requirements.
In the preferred embodiment, the chopper contains at least one web disk wheel having entrained knives that is brought into rotation about a predominantly vertical axis. Thereby, the harvested crop remains can be supplied from above and can be ejected to the rear or to the side in a horizontal direction with respect to the orientation of the combine.
In principle, it would be conceivable to conduct the harvested crop remains to the web disk wheel by the action of gravity alone. However, the harvested crop remains produced by the threshing and separating arrangement of the combine are preferably conducted to the web disk wheel chopper by at least two interacting supply rolls which rotate in opposite directions and between which the harvested crop remains are conveyed. The supply rolls precompress the crop material and forcibly conduct the material to the web disk wheel. Thereby the harvested crop remains are supplied to the web disk wheel chopper in an orderly manner as a mat. It is also conceivable that two pairs of supply rolls be arranged one pair behind the other in the direction of material flow, or to employ an odd number of supply rolls. Rolls with tines or a reaping device in the form of a reel could also be employed as supply rolls.
To control the length of cut, the rotational speed of the supply rolls can be adjustable. An infinitely variable cutting length gearbox can be used to control the supply speed to the chopper arrangement. As an alternative, a gear box having different speeds can also be used.
The use of driven supply rolls makes it possible to provide a shear bar at the inlet of the chopper arrangement. This results in a clean cut with low power requirements.
In case the capacity of a chopper arrangement with only one web disk wheel is not sufficient, an obvious solution would be to arrange two web disk wheels alongside one another. Their axes of rotation can extend parallel or be inclined to each other. It is conceivable that the two web disk wheels be installed in a common housing or to employ two separate housings.
It is also conceivable that a relatively large web disk wheel can be used that is supplied by two inlets that are opposite one another, each of which is supplied with a part of the flow of the crop material. A single such web disk wheel could be used, or two (or even more) smaller ones could be arranged alongside one another.
In a preferred embodiment, the housing of the chopper arrangement is provided with one or more ejection ducts through which the chopped crop material is ejected. The ejection duct, or an end piece mounted to the duct, can be pivoted about a vertical axis in order to eject the chopped crop material in differing directions. The pivoting movement can be continuous in order to distribute the harvested crop remains over the width of a swath taken up by the combine. It is also conceivable that the ejection duct or ducts could be pivoted on the basis of the wind direction or the inclination of the terrain, and to leave them in a fixed position on the basis of a measured condition or provided as input by an operator.
Fundamentally, a web disk wheel is sensitive to foreign objects. In a combine, metallic parts frequently reach the chopper arrangement. These parts may originate with the combine itself, such as crop lifters, intake fingers or pegs of a separator rotor. Therefore, it is preferred that a foreign object detection arrangement be located along the flow of the harvested crop remains upstream from the chopper arrangement. This detector can recognize any foreign objects contained in the flow of the crop material from the separating assembly. The detector controls an arrangement that stops the flow of the crop material (interrupts) or deflects the flow of crop material when a foreign object is detected, so that the foreign object does not reach the web disk wheel. When the foreign object detection arrangement has performed an interruption of the flow of the crop material, the operator can then remove the foreign object before renewing operations. If the flow of crop material is redirected past the chopper arrangement, then the flow of the harvested crop remains can again be automatically conducted into the chopper arrangement, as soon as a sufficiently long time interval has elapsed after the detection of the foreign object. In this way, an interruption of the operation of the combine is avoided. The foreign object detection arrangement may, for example, be configured as an inductive metal detector or operate as an ultra-sonic device, or any other appropriate configuration.